The application of electrical energy to injured tissues has been an acceptable mode of medical therapy for many years and is well characterized. For instance, U.S. Pat. No. 4,846,181 to Miller, issued on Jul. 11, 1989, lists eleven technical articles on the subject of electrotherapy. Those articles suggest, among other ideas, that: application of electrical stimulation can promote wound healing; that electrical stimulation can be applied to wounds in the presence of saline; that low intensity direct current can be utilized as the applied electrical stimulation; that applied low intensity direct current stimulation can be switched between negative and positive polarities during the course of treatment; that high voltage, low amperage galvanic stimulation can be applied for short treatment pulses that are periodically repeated.
In addition, several patents have also been issued directed to promoting healing by electrical stimulation. Included in these patents are the following:
______________________________________ Patent Number Inventor Issue Date ______________________________________ 2,099,511 Caesar 11/16/37 3,918,459 Horn 11/11/75 3,964,477 Ellis et al 6/22/76 4,019,510 Ellis 4/26/77 4,233,965 Fairbanks 11/18/80 4,312,340 Donadelli 01/26/82 4,313,438 Greatbatch 02/02/82 4,314,554 Greatbatch 02/09/82 4,556,051 Maurer 12/3/85 ______________________________________
The above-listed patents include showings that: electrical stimulation can utilize preselected treatment times between a few minutes to a few hours; the polarity of the active electrode can be switched during the course of treatment, and that pulses can be utilized as electrical stimulation.
U.S. Pat. No. 4,989,605 to Rossen discloses an example of known transcutaneous electrical nerve stimulation (TENS) devices. The Rossen device outputs between 25 microamps to 9000 microamps of a monophasic sequence of bursts of a D.C. carrier signal (10,000 Hz to 19,000 Hz) which is modulated off and on in time at a frequency selected from the range 0.3 Hz to 10,000 Hz. The Rossen device's bursts are characterized as having a periodicity greater in duration than that associated with the modulation frequency. In addition, Rossen suggests reversing the polarity of the electrodes periodically during treatment.
Another patent, U.S. Pat. No. 5,397,338 to Grey et. al., discloses another electrotherapy device for pain control and the promotion of tissue healing. The Grey device is capable of operating in either TENS mode, Microcurrent Electrical Neuromuscular Stimulation (MENS) mode, or in lontophoresis mode. The modes are distinguished from each other based on the electrical waveform produced. For instance, the iontophoresis mode utilizes D.C. burst waveforms with currents of from 100 microamps to 4 milliamps. The TENS mode utilizes a positive biphasic or alternating monophasic waveform with currents of from 20 microamps to 20 milliamps. The MENS mode utilizes a monophasic waveform with currents of from 10 microamps to 150 microamps. The Grey device is intended as a multi-purpose unit capable of operating in various modes without requiring the changing of electronic stimulation units or electrodes between modes. However, changing from one mode to another in the Grey device is accomplished by manually altering switch positions, thus the Grey unit does not automatically change from one mode to another.
Existing electrotherapy methods utilize the above described devices, or variations thereof, to subject the tissue to be treated to a particular electrotherapy treatment. Typically, these treatments utilize only a single waveform and/or current setting for the duration of the treatment.